Protein which has a signal sequence, a peptide usually present at the N-terminus of proteins and which is destined to be either secreted or part of membrane components. The signal sequence (usually 20-30 amino acids long) interacts with the signal recognition particle and directs the ribosome to the endoplasmic reticulum where co-translational insertion takes place. Signal peptides are highly hydrophobic but have some positively charged amino acids. Normally, the signal sequence is removed from the growing peptide chain by specific peptidases (signal peptidases) located on the cisternal face of the endoplasmic reticulum.
Category: Domain · UniProtKB (909,609)
|Signal recognition particle|
Protein of the signal recognition particle (SRP) which is a cytosolic ribonucleoprotein complex that induces elongation arrest of nascent presecretory and membrane proteins until the ribosome becomes associated with the rough endoplasmic reticulum or the prokaryotic cytoplasmic membrane.
Category: Cellular component · UniProtKB (20,100)
|Signal transduction inhibitor|
Protein which inhibits signal transduction, the process by which extracellular signals induce intracellular responses. Usually a hormone or neurotransmitter binds to a cell surface receptor which is coupled to a second messenger system, such as that involving cAMP, or to an ion channel. The final downstream consequence of signal transduction is a change in the cell's function, such as a modification in glucose uptake or in cell division. Such a change may be the result of an activation or an inhibition event.
Category: Molecular function · UniProtKB (181)
Single-pass transmembrane protein (type II, III, and IV) possessing a membrane-spanning domain which targets the protein to the ER membrane. Typical features of signal-anchors are the presence of positively charged residues on the amino terminal side followed by an apolar segment of approx. 20 residues. The amino-acid composition is not very different from typical signal sequences.
Category: Domain · UniProtKB (46,493)